Alkylbutyrolactone-alpha-acetic acids



United States Patent M 3,261,782 ALKYLBUTYROLACTONE-oc-ACETIC ACIDSDonald J. Anderson, San Anselmo, and Louis de Vries,

Richmond, Calif., assignors to Chevron Research Company, a corporationof Delaware No Drawing. Filed Mar. 5, 1964, Ser. No. 349,747 2 Claims.(1. 252-57) This application is a continuation-in-part of Donald J.Anderson and Louis de Vries application Serial No. 259,- 722, filedFebruary 19, 1963 (now abandoned).

This invention pertains to lubricating oil compositions havingincorporated therein metal-free detergents.

Present day internal combustion engines operate at high speeds and highcompression ratios. When used in the so-called city stop-and-go driving,which includes the greater part of the driving conditions for a largepercentage of todays automobiles, the internal combustion engines do notreach the most efficient operating temperature. Under city drivingconditions, large amounts of partial oxidation products are formed, andreach the crankcase of the engine by blowing past the piston rings. Mostof these partial oxidation products are oil-insoluble, tending to formdeposits on the various operating parts of the engine, such as thepistons, piston rings, etc. For the purpose of preventing the depositionof these products on the various engine parts, it is necessary toincorporate detergents in the lubricating oil compositions, thus keepingthese polymeric products highly dispersed in a condition unfavorable fordeposition on metals.

For the most part, the various detergents which are added to crankcaseoils to reduce this formation of sludges and varnishes are metal organiccompounds, particularly those compounds wherein the metal is linked toan or ganic group through an oxygen atom. Although thesemetal-containing organic compounds have some effectiveness as detergentsfor dispersing the precursors of deposits Within the oil itself ratherthan permitting them to form added deposits on the engine parts, theyhave the disadvantage of forming ash deposits in the engine. These ashdeposits lower engine performance by fouling spark plugs and valves, andcontribute to preignition.

It is a particular object of this invention to provide new compoundswhich are used in the formation of metal-free detergents for lubricatingoil compositions.

Therefore, in accordance with this invention, it has been discoveredthat alkylbutyrolactone-a-acetic acids are new compounds which areuseful as intermediates in the formation of amides ofalkylbutyrolactone-u-acetic acid. These amides ofalkylbutyrolactone-u-acetic acid are effective as detergents inlubricating oil compositions.

The alkylbutyrolactone-ut-acetic acids described herein are useful notonly as intermediates in the formation of metal-free detergents, butthese alkylbutyrolactone-a-acetic acids are useful as rust inhibitors inlubricating oil compositions.

These acids, which are new compounds, are of the formula o CHCHZCOOH3,261,782 Patented July 19, 1966 wherein R R and R are hydrogen or alkylradicals containing a total of from 10 to 300 carbon atoms. The totalnumber of carbon atoms in R R and R is preferably from 10 to 100.

These alkyl butyrolactone-a-acetic acids can be prepared by reacting anolefinic hydrocarbon with dimethyl bromosuccinate to obtain the methylester which is then converted to the acid.

The amides of the above-described alkylbutyrolactonea-acetic acid arethose derived from ammonia or amines, including aliphatic,cycloaliphatic and aromatic monoamines, polyamines and heterocyclicamines. In any case, the amino group reacting with the carboxyl groupsto form the amide must be a primary or secondary amino group.

The resulting amides include those of the formula wherein R R and R arethe same as defined hereinabove, and R is hydrogen or the residue of anamine radical having from 1 to 20 carbon atoms, preferably from 2 to 12carbon atoms, and from O to 10 nitrogen atoms.

Of particular preference as lubricating oil additives are the gammaalkylbutyrolactone-u-acetic acids wherein the gamma alkyl radicalcontains from 10 to 300 carbon alkyl radical containing from 10 to 300carbon atoms, and atoms; that is, wherein R in the above formula is an Rand R are hydrogen.

Lubricating oils which can be used as base oils when thesealkylbutyrolactone-a-acetic acids are used therein include a widevariety of lubricating oils, such as naphthenic base, paraifin base, andmixed base lubricating oils, other hydrocarbon lubricants, e.g.,lubricating oils derived from coal products, and synthetic oils, e.g.,alkylene polymers (such as polymers of propylene, butylene, etc., andmixtures thereof), alkylene oxide-type polymers (e.g., propylene oxidepolymers) and derivatives, including alkylene oxide polymers prepared bypolymerizing the alkylene oxide in the presence of water or alcohols,e.g., ethyl alcohol, di-car'boxylic acid esters (such as those which areprepared by esterifying such dicarboxylic acids as adipic acid, azelaicacid, suberic acid, sebacic acid, alkanol succinic acid, fumaric acid,maleic acid, etc., with alcohols such as butyl alcohol, hexyl alcohol,Z-ethylhexyl alcohol, dodecyl alcohol, etc.), liquid esters of acids ofphosphorus, alkyl benzenes (e.g., monoalkyl benzene such as dodecylbenzene, tetradecyl benzene, etc.) and dia'lkyl benzenes (e.g.,n-nonyl-Z-ethylhexy-l benzene), polyphenyls (e.g., 'biphenyls andtenphenyls), alkyl biphenyl ethers, compounds of silicon, e.g.,tetraethyl silicate, tetraisopropyl silicate,tetra(4-methyl-2-tetraethyl) silicate, hexyl-(4- methyLZ-pentoxy)disiloxane, poly(-met hyl) siloxane, poly(methylpheny-l) siloxane, etc.

The above base oils may he used individually or in combinations thereof,wherever miscible or wherever made so by the use of mutual solvents.

When used as rust inhibitors the alkylbutyrolactone-aacetic acids can beused in oils of lubricating viscosity in amounts of 0.1% to 10% byweight, preferably 0.25% to by weight.

The preparation of the alkylbutyrolactone-a-acetic acids describedherein is illustrated in the following examples.

EXAMPLE 1.PREPARATION OF THE METHYL ESTER OFPOLYBUTENYLBUTYROLACTONE-oc- ACETIC ACID A mixture of 93.8 g. (0.1 mole)of a polybutene (molecular weight of about 840) in 100 ml. heptane, 225g. (1 mole) of dimethyl bromosuccinate, and 1.46 g. (0.01 mole) ofdi-t-butyl peroxide was charged to a rocker bomb, and the vessel purgedwith nitrogen. The reaction mixture was heated at 130 C. with agitationfor 5 hours, then cooled to room temperature, and the methyl bromidevented to the atmosphere. The reaction mixture was vacuum distilled toremove the heptane and the unreacted dimethyl bromosuccinate.

Infrared analysis of the product showed the spectrum characteristics ofthe lactone (1780 cmr and the ester (1735 cmf EXAMPLE 2.PR'EPARATION OFTHE METHYL ESTER OF DECYLBUTYROLACTONE-oc-ACETIC ACID A mixture of 98.5g. (0.438 mole) of dimethyl bromosuccinate, 14.7 g. (0.0875 mole)l-dodecene, 1.0 g. (0.00875 mole) of acetyl peroxide in 9 ml. ofdimethyl phthalate, and 50' ml. benzene was heated with agitation for 4hours at 90 C. The benzezne and unreacted dimethyl bromosuccinate wereremoved by distillation at reduced pressure, followed by heating theresidual yellow oil for minutes at 195-205 C. at an absolute pressure of2 mm. Hg. The final residue was crystallized from an ether-pentanesolvent, resulting in a light brown waxy solid having a melting pointrange at 3237 C. Infrared analysis of this product showed the spectrumcharacteristics of a lactone at 1775 cm? and the ester at 1735 CIILTI.

Further purification resulted in white crystals which had a meltingpoint of 4345 C. Elemental analysis showed:

Calculated: 68.40% C., 10.14% H. Found: 68.35% C., 8.19% H.

The following equations exemplify the reactions of Example 2:

CH3 CH2 0CH=CH2 BrCHOOCI-Ia CHzCOOCI-Is I CH3(CH2)9CHCH2CI'ICOOCHs 1Heat CII3(CH2)DGIICH2OI-ICOCOH3 OHtCOOGI-Ia The methyl ester ofdecylbutyrolactone-a-acetic acid prepared above was converted to thecorresponding acid. A mixture of 2 g. of lactone ester, 50 ml. of 96%sulfuric acid and 50 g. of ice were stirred and warmed to 100 C., atwhich temperature the stirring was continued for about 3 hours. Themixture was cooled until the lactone acid crystallized on top of thesulfuric acid. The lactone acid was then extracted with diethyl etherusing ten separate ml. extractions. The combined ether extracts werechilled in a Dry Ice-acetone bath. The extracts were then filtered toseparate the lactone acid in the form of white crystals. Infraredanalysis of a melt-smear of the white crystals gave the expected peaksof a lactone acid. Further recrystallization of the white crystals fromether yielded a sample having a melting point of 104 C., the analysis ofwhich showed a percent carbon of 67.73 and percent hydrogen of 9.68corresponding to theoretical values of 67.61 and 9.86, respectively.

The lactone acids of the invention are useful themselves as rustinhibitors in lubricating oil compositions in the formulations describedabove. However, another important feature is their utility asintermediates for reaction with various amines to provide effectivenitrogen containing ashless detergents for lubricants.

The following example illustrates the use of thealkylbutyrolactone-a-acetic acids as intermediates in the formation ofthe corresponding amides which are effective as detergents inlubricating oil compositions.

EXAMPLE 3.-PREPARATION OF TETRAETHYL- ENE PENTAMINE AMIDE OF AN ALKYLBU-TYRLACTONE-u-ACETIC ACID DERIVED FROM A BUTYLENE POLYMER Analkylbutyrolactone-a-acetic acid was prepared from a butylene polymerhaving -a molecular weight of about 850. A 40% solution of this lactonein a hydrocarbon oil was reacted with an ethylene amine condensationproduct having a molecular weight corresponding to tetraethylenepent-amine.

A mixture of 76 g. (0.4 mole) of this tetraethylene pentamine and 1218g. (0.50 mole) of the the product of the alkylbutyrolactone-a-aceticacid was blended with agitation at 150 C. for one hour, allowed to cool,then stand for 36 hours at room temperature. The mixture 7 was thenreheated at 150 C. for 1 hour.

Infrared analysis showed a band at 1650-1700 cm. due to the amidecarbonyl group, and a band at 1775 cm." due to the butyrolactonecarbonyl group.

Table I hereinbelow presents data obtained with several illustrativetests of derivatives. Tests B and C are lubricating oil compositionscontaining 1% by weight of the amide obtained in Example 3 hereinabovein combination with metal dithiophosphates. Tests D and E arelubricating oil compositions containing 1.5% of amides derived fromtriethylene tetramine and diethylene triamine, respectively. Theconcentration of the dithiophosphates is expressed in millimoles perkilogram of finished composition (based on the metal), that is, mM./kg.

Dithiophosphate A was a zinc salt of a mixed dialkyl dithiophosphatewherein one of the alkyl radicals contained 4 carbon atoms and the otheralkyl radical contained 5 carbon atoms. Dithiophosphate B was a zincdialkylphenyl dithiophosphate.

The test was made in a Caterpillar L1 engine according to Supplement Iconditions for a period of 120 hours as described in the CoordinatingResearch Council Handbook, January, 1946.

The PD Nos. refer to the piston discoloration rating. After the enginetest, the three piston lands are examined visually. To a piston skirtwhich is completely black is assigned a PD number of 800; to one whichis completely clean, a PD number of 0; to those intermediate betweencompletely black and completely clean are assigned PD numbersintermediate in proportion to the extent and degree of darkening.

The GD Nos. refer to the percentage deposits in the piston ring grooves;a 0 evaluation being a clean groove; and a number of being a groove fullof deposits.

The base oils were California SAE 30 base oils.

1 These te t results were obtained in a Caterpillar L-l te t under theMIL-L2104 conditions. Thus, under the more severe Supplement-1conditions, these GD Nos. would be considerably higher.

Table II hereinbelow presents data obtained in an FL-2 test, using a6-cylinder Chevrolet engine operating at 2500 rpm. for a period of 36hours, which test is fully described in a Coordinating Research Councilbulletin titled Research Technique for the Determination of the Effectsof Fuels and Lubricants on the Formation of Deposits During ModerateTemperature Operation" (1948).

The piston varnish rating is a visual observation of the amount ofvarnish on a piston skirt, with 10 being the maximum rating for aperfectly clean piston, and 0 being the rating of a piston fully coveredwith black varnish. This piston varnish rating correlates with roadperformance in automobiles.

The total rating is the overall deposit rating of the engine, with therating values ranging from 0, the poorest value, to 100, the top value.These figures indicate the percentage rating for the engine.

The base oil was an SAE 30 base oil.

The succinirnide and the dithiophosphates were the same as thosedescribed for Table I hereinabove.

In an L-38 strip corrosion test, the copper strip weight loss was only15.5 milligrams when using a petroleum base oil containing 6% by weightof the amide prepared as in Example 3 hereinabove.

Table III hereinbelow presents data obtained in an L38 engine test,using a l-cylinder CLR engine. The test period was for 40 hours.

T able III Additive:

Amide (Example 3), wt. percent 2.0 Dithiophosphate A, mM./kg. 10Dithiophosphate B, mM./kg 2 Test results: Bearing weight loss (mgs) 55.4

wherein R R and R are selected from the group consisting of hydrogen andalkyl radicals having a total of from 10 to 300 carbon atoms.

2. A lubricating oil composition comprising a major proportion of an oilof lubricating viscosity, and from 0.25% to 5% by weight of analkylbutyrolactone-aacetic acid of the formula wherein R R and R areselected from the group consisting of hydrogen and alkyl radicals havinga total of from 10 to 300 carbon atoms.

References Cited by the Examiner UNITED STATES PATENTS 6/1958 Nemec260343.6 11/1964 Prill et al 260343.6

OTHER REFERENCES Kharasch: J our. American Chem. Soc. (1948), pages1055-1059.

DANIEL E. WYMAN, Primary Examiner.

W. H. CANNON, Assistant Examiner.

1. A LUBRICATING OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF AN OILOF LUBRICATING VISOCITY, AND FROM 0.1% TO 10% BY WEIGHT OF ANALKYLBUTYROLACTONE-AACETIC ACID OF THE FORMULA